Hello. Hopefully a native speaker will get to your question. Until then, this may help: ပက်လက် can mean 'helplessly'. ဝမ်းနည်းပက်လက် can mean 'in great sorrow; in utter desolation'. So, the full sentence translated can mean someone "speaks in great sorrow", etc I took these definitions from the following (very useful) resource: http://sealang.net/burmese/dictionary.htm Bonne chance !

Well it means “Say sadly” it could be sad for yourself or for someone else according to what you are saying

We use those words when we felt grief / grieve for someone or about something and talking with this sorrow. The situation is hopeless and helpless for ourselves or someone.